This invention relates to improvements in a continuous loop mouse of the general type described in U.S. Pat. Nos. 5,442,377, 5,479,190 and 5,493,314 and which patents are incorporated herein by reference thereto. In particular, the present invention relates to an improved support cage or track and an indexing wheel with, and without x-axis movement detection, which reduce frictional forces to enable ease of loop movement and increased loop movement detection sensitivity.
The typical devices currently used for computer screen cursor or pointing control consist of mouse-type and trackball-type and joystick-type control devices. The mouse-type and trackball-type devices utilize an individual sphere which is supported on bearings to permit rotation of the sphere in any direction. The motion detection components are biased against the sphere to permit detection of sphere movement. The sphere movement is converted into X-axis and Y-axis components which are then utilized to reposition a pointing device or cursor on a computer screen or other graphical user interface device. Devices in which the sphere is enclosed in a housing so that the sphere travels in contact with a surface while the housing manipulated by a user are denominated as mouse-type devices. Devices in which the housing supports the sphere for direct manipulation by a user are generally referred to as trackball-type devices.
A third type of device has become prominent with laptop computers which consists of a "joystick" projecting from the center of the keyboard. The joystick is mobile about a central pivot axis. The joystick movement is converted into X-axis and Y-axis components which are then communicated to a pointing device or cursor on a computer screen or other graphical user interface to reposition the pointing device.
The problems associated with the first two devices--the mouse and the trackball--have been discussed in U.S. Pat. Nos. 5,442,377, 5,479,190 and 5,493,314. The problems associated with the joystick-type device are mainly related to the short range of motion, or short throw, presented by the small joystick which projects from the keyboard. The user must develop an ability to make very fine manipulations of the joystick or the user will constantly over-shoot the desired location when repositioning the pointer or the computer screen. The advantage of the joystick device is that the user does not have to lift the hands from the keyboard as with the mouse or the trackball.
The embodiments described in U.S. Pat. Nos. 5,442,377, 5,479,190 and 5,493,314 provide a useful alternative to the above devices and have the advantage of being located on the keyboard so the user does not have to lift the hands from the keyboard. In addition, these devices are superior to the joystick as a greater range of movement is available to the user so the problems associated with the joystick devices are not present.
However, in one embodiment of the type of inventions shown in U.S. Pat. Nos. 5,442,377, 5,479,190 and 5,493,314 --the annular array of multiple spheres embodiments--the movement of the spheres by the user requires that the spheres be pressed around two curves in order to provide the continuous loop aspect of the device. While operating as intended, the pushing of the spheres through the two curved portions of the housing results in frictional drag against the track sides and the side to side close contact between the spheres reduces the rolling ability of the spheres. These two attributes increase the amount of lateral force required from the user in order to manipulate the spheres into new positions.
Therefore, it will be appreciated that the need is present for an improvement to the annular array of multiple spheres which reduces this frictional inhibition to sphere movement at the curved sections of the housing and reduces the amount of lateral force which a user must provide in order to push the spheres through the two curved portions of the track. In addition the need is present to reduce the frictional resistance and reduce the needed user-provided lateral force in order to increase control of sphere movement and thereby increase sensitivity of the detection apparatus for the repositioning of a cursor laterally or in the direction of the X-axis.